The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Sep. 02, 2003

Filed:

Mar. 19, 2002
Applicant:
Inventors:

Jian-Hsing Lee, Hsin-Chu, TW;

Kuo-Reay Peng, Tainan, TW;

Shui-Hung Chen, Hsin-Chu, TW;

Jiaw-Ren Shih, Hsin-Chu, TW;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11C 1/604 ;
U.S. Cl.
CPC ...
G11C 1/604 ;
Abstract

A combination erase method to erase data from a flash EEPROM eliminates electrical charges trapped in the tunneling oxide of a flash EEPROM to maintain proper separation of the programmed threshold voltage and the erased threshold voltage after extended programming and erasing cycles. A first embodiment method to erase a flash EEPROM cell begins by negative gate erasing to remove charges from the floating gate, followed by a source erasing to further remove charges from the floating gate, and finally followed by a channel erasing to detrap charges. A second embodiment begins with a negative gate erasing having a incremental stepping of the voltages to remove the charges from the floating gate. This followed by a source erasing to detrap the tunneling oxide of the EEPROM cell. A third embodiment begins with a source erasing having a incremental stepping of the voltages to remove the charges from the floating gate. This followed by a channel erasing to detrap the tunneling oxide of the EEPROM cell.


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